The present invention relates generally to headrests for motor vehicle seats and, more particularly, to such headrests which are vertically displaceable by means of remote control devices.
A vertical-displacement device of this type for a headrest is shown and described in German Published Unexamined Application (Offenlegungsschrift) No. 2,925,781. In this document, the adjusting movement introduced via the remote control device is transmitted to a gearwheel and from this to a rack. The headrest has two support rods which are guided by means of sliding members and which are connected to the backrest frame via rails of U-shaped profile extending in the direction of the support rods. However, both the rails and the support rods are respectively connected to one another by bridge means. These bridge means serve to receive gearwheel and rack means. This arrangement results not only in a stiffening of the seat, which has an adverse influence on the springing properties when the strength of the rest is maintained, but also in a reduction in the upholstery thickness at least in the region between the rails. Moreover, the installation and especially the removal of a headrest of this type are extremely difficult, and it is not possible simply to pull out the headrests of unoccupied seats to increase visibility. Further, motor vehicle seats are often equipped only at special request with such headrests which are vertically displaceable via remote control, so that different headrest designs are necessary when non-remote control adjustment principles are used.
It is therefore an object of the present invention to provide a headrest means vertically displaceable by means of remote control devices which can be installed and removed easily.
Another object of the present invention is the provision of headrest means in which the gear components necessary for executing the lifting movement are arranged so that stiffening of the seat and a substantial reduction in the upholstery thickness are avoided.
Yet another object of the present invention is to provide a headrest means which will be of identical design for seats with and without remotely actuable vertical displacement.
These and other objects of the present invention are achieved in the provision of a headrest of the type mentioned herein above which is vertically displaceable by remote control, wherein at least one support rod is received releasably at its free end by a coupling which projects from the top end of a rack means extending along the supporting rail, and wherein housing means which receives the gearwheel and guides the rack means is also supported on the rail.
The amount of housing which projects beyond the rail can be reduced even further while maintaining good headrest displacement force transmission if the rack has the form of a ladder, the rungs of which act as the teeth of the rack when engaging the gearwheel.
According to especially preferred embodiments of the invention, the support rod can be coupled and uncoupled in a simple way by providing that the rack is formed from resilient material and the coupling is designed as a spring engagement means which, when the headrest is fully extended, can be pressed sideways by the free end of a leaf spring fastened to the bottom of the rail until the engagement with the support rod is cancelled.
In a further embodiment of the present invention, the free end of the leaf spring is provided with an actuating pin which passes through an orifice in the rail in the direction of the rear wall of the backrest. This pin can readily be felt through the upholstery covering and pressed in.
Further objects, features, and advantages of the present invention will become more apparent from the following description when taken with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.